Since the discovery of serotonin (5-hydroxytryptamine, 5-HT) over four decades ago, the cumulative results of many diverse studies have indicated that serotonin plays a significant role in the functioning of the mammalian body, both in the central nervous system and in peripheral systems as well. Morphological studies of the central nervous system have shown that serotonergic neurons, which originate in the brain stem, form a very diffuse system that projects to most areas of the brain and spinal cord. R. A. O""Brien, Serotonin in Mental Abnormalities, 1:41 (1978); H. W. M. Steinbusch, Handbook of Chemical Neuroanatomy, Volume 3, Part II, 68 (1984); N. E. Anden, et al., Acta Physiologica Scandinavia, 67:313 (1966). These studies have been complemented by biochemical evidence that indicates large concentrations of 5-HT exist in the brain and spinal cord. H. W. M. Steinbusch, supra.
With such a diffuse system, it is not surprising that 5-HT has been implicated as being involved in the expression of a number of behaviors, physiological responses, and diseases which originate in the central nervous system. These include such diverse areas as sleeping, eating, perceiving pain, controlling body temperature, controlling blood pressure, depression, schizophrenia, and other bodily states. R. W. Fuller, Biology of Serotonergic Transmission, 221 (1982); D. J. Boullin, Serotonin in Mental Abnormalities 1:316 (1978); J. Barchas, et al., Serotonin and Behavior, (1973).
Serotonin plays an important role in peripheral systems as well. For example, approximately 90% of the body""s serotonin is synthesized in the gastrointestinal system, and serotonin has been found to mediate a variety of contractile, secretory, and electrophysiologic effects in this system. Serotonin may be taken up by the platelets and, upon platelet aggregation, be released such that the cardiovascular system provides another example of a peripheral network that is very sensitive to serotonin. Given the broad distribution of serotonin within the body, it is understandable that tremendous interest in drugs that affect serotonergic systems exists. In particular, receptor-specific agonists and antagonists are of interest for the treatment of a wide range of disorders, including anxiety, depression, hypertension, migraine, compulsive disorders, schizophhrenia, autism, neurodegenerative disorders, such as Alzheimer""s disease, Parkinsonism, and Huntington""s chorea, and cancer chemotherapy-induced vomiting. M. D. Gershon, et al., The Peripheral Actions of 5-Hydroxytryptamine, 246 (1989); P. R. Saxena, et al., Journal of Cardiovascular Pharmacology, 15:Supplement 7 (1990).
Serotonin produces its effects on cellular physiology by binding to specialized receptors on the cell surface. It is now recognized that multiple types of receptors exist for many neurotransmitters and hormones, including serotonin. The existence of multiple, structurally distinct serotonin receptors has provided the possibility that subtype-selective pharmacologic agents can be produced. The development of such compounds could result in new and increasingly selective therapeutic agents with fewer side effects, since activation of individual receptor subtypes may function to affect specific actions of the different parts of the central and/or peripheral serotonergic systems.
An example of such specificity can be demonstrated by using the vascular system as an example. In certain blood vessels, stimulation of 5-HT1-like receptors on the endothelial cells produces vasodilation while stimulation of 5-HT2 receptors on the smooth muscle cells produces vasoconstriction.
Currently, the major classes of serotonin receptors (5-HT1, 5-HT2, 5-HT3, 5-HT4, 5-HT5, 5-HT6, and 5-HT7) contain some fourteen to eighteen separate receptors that have been formally classified based on their pharmacological or structural differences. [For an excellent review of the pharmacological effects and clinical implications of the various 5-HT receptor types, see Glennon, et al., Neuroscience and Behavioral Reviews, 14:35 (1990).]
Pollen has long been recognized as a cause of allergic rhinitis commonly called xe2x80x9chay feverxe2x80x9d. Pollen contains proteases which induce the release of mediators from mast cells, thereby stimulating IgE biosynthesis. The granulation of mast cells by IgE results in the release of histamines which leads to an inflammatory response which causes congestion, itching, and swelling of sinuses. Many eosinophils are present in allergic patients with nasal mucus and neutrophils are present in patients with infected mucus.
Antihistamines are drugs commonly utilized which, when taken orally, frequently have a sedative effect. Alternatively, nasal sprays containing cromolyn sodium have been effective as cromolyn acts by clocking the reaction of the allergen with tissue mast cells. Cromolyn is not entirely effective, however, as it apparently does not bind to some of the mediators of inflammation or the activators of IgE biosynthesis that stimulate the degranulation of mast cells and the production of histamines from the mast cells.
Inflammation is a non-specific response of tissues to diverse stimuli or insults and results in the release of materials at the site of inflammation that induce pain. It is now recognized that mast cells, neutrophils, and T-cells are implicated in the pathophysiology of inflammatory skin conditions as well as in other physiological disorders. Mast cells provide the greatest source of histamines in acute inflammation, as well as chymases, after degranulation by IgE.
The xe2x80x9ccommon coldxe2x80x9d is a time honored phrase used by both physicians and lay persons alike for the identification of acute minor respiratory illness. Since the identification of rhinovirus in 1956, a considerable body of knowledge has been acquired on the etiology and epidemiology of common colds. It is known that the common cold is not a single entity, but rather is a group of diseases caused by members of several families of viruses, including parainfluenza viruses, rhinoviruses, respiratory syncytial viruses, enteroviruses, and coronaviruses. Much work has been performed in characterizing viruses which cause the common cold. In addition, the molecular biology of rhinoviruses, the most important common cold viruses, is understood in great detail. In contrast, progress on the treatment of common colds has been slow despite these advances. While there are now large numbers of compounds that have been found to exhibit antiviral activity against cold viruses in cell culture, antiviral compounds have had limited effectiveness in patients.
Because of the widespread dissatisfaction with the currently marketed treatments for the common cold and allergic rhinitis within the affected population, there exists a need for a more efficacious and safe treatment.
This invention provides methods for the treatment or amelioration of the symptoms of the common cold or allergic rhinitis in a mammal which comprise administering to a mammal in need thereof an effective amount of a composition having serotonin 5-HT1F agonist activity.
The term xe2x80x9callergic rhinitisxe2x80x9d as employed herein is understood to include rhinitis medicamentosa, rhinitis sicca, and atrophic rhinitis.
Many serotonin binding receptors have been identified. These receptors are generally grouped into seven classes on the basis of their structure and the pharmacology of the receptor as determined by the binding efficiency and drug-related characteristics of numerous serotonin receptor-binding compounds. In some of the groups several subtypes have been identified. [For a relatively recent review of 5-hydroxytryptamine receptors, see, E. Zifa and G. Fillion, Pharamcological Reviews, 44:401-458 (1992); D. Hoyer, et al., Pharamcological Reviews, 46:157-203 (1994). The Hoyer, et al., reference describes for each class or subtype one or more compounds which have efficacy as antagonists or agonists for the receptor.]
The 5-HT1 family includes subtypes which can be grouped together based on the absence of introns in the cloned genes, a common G-coupled protein transduction system (inhibition of adenylate cyclase), and similar operational characteristics. The 5-HT1 family of inhibitory receptors includes subtypes A, B, D, E, and F. The 5-HT1 G protein-linked receptors generally inhibit the production of cyclic adenosine monophosphate (cAMP), while the 5-HT2 G protein linked receptors stimulate phosphoinosytol hydrolysis.
The 5-HT1A receptor was the first cloned human serotonin receptor. Activated 5-HT1A receptors expressed in HeLa cells inhibit forskolin-stimulated adenylate cyclase activity. The 5-HT1D receptor was originally identified in bovine brain membrane by Heuring and Peroutka. R. E. Heuring and S. J. Peroutka, Journal of Neuroscience, 7:894-903 (1987). The 5-HT1D receptors are the most common 5-HT receptor subtype in the human brain and may be identical to the 5-HT1-like receptor in the cranial vasculature. S. D. Silberstein, Headache, 34:408-417 (1994). Sumatriptan and the ergot alkaloids have high affinity for both the human 5-HT1D and the 5-HT1B receptors. Id.
The 5-HT1F subtype of receptor has low affinity for 5-carboxamidotryptamine (5-CT) unlike the other 5-HT receptors, except for the 5-HT1E subtype. Unlike the 5-HT1E receptors, however, the 5-HT1F receptors do show affinity for sumatriptan.
The biological efficacy of a compound believed to be effective as a serotonin 5-HT1F agonist may be confirmed by first employing an initial screening assay which rapidly and accurately measures the binding of the test compound to the serotonin 5-HT1F receptor. Once the binding of the test compound to the serotonin 5-HT1F receptor is established, the in vivo activity of the test compound on the receptor is established.
Serotonin Receptor Binding Activity
Binding to the 5-HT1F Receptor
The ability of a compound to bind to a serotonin receptor was measured using standard procedures. For example, the ability of a compound to bind to the 5-HT1F receptor substype was performed essentially as described in N. Adham, et al., Proceedings of the National Academy of Sciences (USA), 90:408-412 (1993).
The cloned 5-HT1F receptor was expressed in stably transfected LM(tkxe2x88x92) cells. Membrane preparations were made by growing these transfected cell lines to confluency. The cells were washed twice with phosphate-buffered saline, scraped into 5 ml of ice-cold phosphate-buffered saline, and centrifuged at 200xc3x97g for about five minutes at 4xc2x0 C. The pellet was resuspended in 2.5 ml of cold Tris buffer (20 mM Tris.HCl, pH 7.4 at 23xc2x0 C., 5 mM EDTA) and homogenized. The lysate was centrifuged at 200xc3x97g for about five minutes at 4xc2x0 C. to pellet large fragments. The supernatant was then centrifuged at 40,000xc3x97g for about 20 minutes at 4xc2x0 C. The membranes were washed once in the homogenization buffer and resuspended in 25 mM glycylclycine buffer, pH 7.6 at 23xc2x0 C.
Radioligand binding studies were performed using [3H]5-HT (20-30 Ci/mmol). Competition experiments were done by using various concentrations of drug and 4.5-5.5 nM [3H]5-HT. Nonspecific binding was defined by 10 xcexcM 5-HT. Binding data were analyzed by nonlinear-regression analysis. IC50 values were converted to Ki values using the Cheng-Prusoff equation.
Serotonin Agonist Activity
Adenylate Cyclase Activity
Adenylate cyclase activity was determined in initial experiments in LM(tkxe2x88x92) cells, using standard techniques. See, e.g., N. Adham, et al., supra,; R. L. Weinshank, et al., Proceedings of the National Academy of Sciences (USA), 89:3630-3634 (1992), and the references cited therein.
Intracellular levels of cAMP were measured using the clonally derived cell line described above. Cells were preincubated for about 20 minutes at 37xc2x0 C. in 5% carbon dioxide, in Dulbecco""s modified Eagle""s medium containing 10 mM HEPES, 5 rnM theophylline, and 10 xcexcM pargyline. Varying concentrations of the test compounds were added to the medium to determine inhibition of forskolin-stimulated adenylate cyclase.
Animal Models for Measuring Nasal Extravasation in Guinea Pigs and Rats
Electrical Stimulation of the Trigeminal Ganglion
A guinea pig or rat is anesthetized and placed in a stereotaxic frame. Following midline sagittal scalp incisions, two pairs of stimulating electrodes are lowered into the trigeminal ganglion. The femoral artery is exposed and a 50 mg/kg dose of Evans blue dye is injected intravenously. The Evans blue dye complexes with proteins in the blood and functions as a marker for protein extravasation. Two minutes after the Evans blue injection, the left trigeminal ganglion is stimulated for 3 minutes at a current density of 1.0 mA (5 Hz, 4 msec duration). Fifteen minutes following the stimulation the animals are euthanised by exsanguination with 40 mL of saline perfused through the heart. The nose is cut immediately behind the incisors to collect the nasal mucosal tissue and turbinates of the rostal part of the nose. The nasal dorsum is then removed to expose the nasal cavity. The mucosa and parts of the naso- and maxilloturbinates are removed and weighed. These tissues are then incubated in 4 mL dimethylformamide for 18 to 24 hours to extract the extravasated Evans blue dye. The dimethylformamide extracts are quantified by measuring the optical density at 620 nm with a spectrophoto-meter. The concentration of Evans blue dye extravasated into the tissues is interpolated from a concentration standard curve of Evans blue in dimethylformamide. The ability of 5-HT1F agonists to block the Evans blue extravasation into the nasal tissues is assessed by dosing the test animals with a 5-HT1F agonist intravenously 8 minutes prior to the injection of the Evans blue dye.
Intravenous Injection and Nasal Instillation of Meta-chlorophenylpiperazine (mCPP) or Nitroglycerin
Protein extravasation by the trigeminal ganglion may also be stimulated by either intravenous injection or nasal instillation of mCPP or nitroglycerin. A guinea pig or rat is anesthetized and the femoral artery is exposed. The animal is then either injected with an intravenous dose of mCPP or nitroglycerine, or a dose of mCPP or nitroglycer-ine is instilled into the nasal cavity directly. Two minutes after administration of mCPP or nitroglycerine, a 50 mg/kg dose of Evans blue dye is injected intravenously. Fifteen minutes following the Evans blue injection, the animals are euthanised by exsanguination with 40 mL of saline perfused through the heart. The nose is cut immediately behind the incisors to collect the nasal mucosal tissue and turbinates of the rostal part of the nose. The nasal dorsum is then removed to expose the nasal cavity. The mucosa and parts of the naso- and maxilloturbinates are removed and weighed. These tissues are then incubated in 4 mL dimethylformamide for 18 to 24 hours to extract the extravasated Evans blue dye. The dimethylformamide extracts are quantified by measuring the optical density at 620 nm with a spectrophoto-meter. The concentration of Evans blue dye extravasated into the tissues is interpolated from a concentration standard curve of Evans blue in dimethylformamide. The ability of 5-HT1F agonists to block the Evans blue extravasation into the nasal tissues is assessed by dosing the test animals with a 5-HT1F agonist intravenously 8 minutes prior to the injection of the Evans blue dye.
The term xe2x80x9c5-HT1F agonistxe2x80x9d, as it is used in the description of this invention, is taken to mean a full or partial agonist. A compound which is a partial agonist at the 5-HT1F receptor must exhibit sufficient agonist activity to provide the desired biological effect at an acceptable dose. While a partial agonist of any intrinsic activity may be useful for the method of this invention, partial agonists of at least about 50% agonist effect (Emax) are preferred and partial agonists of at least about 80% agonist effect (Emax) are more preferred. Full agonists at the 5-HT1F receptor are most preferred.
A number of serotonin 5-HT1F agonists are known in the art and are useful for the method of the present invention. One such class of compounds are optionally substituted 3- less than 1,2,3,6-tetrahydro- less than 1-alkyleneheteroaryl greater than -4-pyridinyl greater than -1H-indoles and 3- less than 1-alkyleneheteroaryl greater than -4-piperidinyl greater than -1H-indoles of Formula I: 
in which
Axe2x80x94B is xe2x80x94CHxe2x80x94CH2xe2x80x94 or xe2x80x94Cxe2x95x90CHxe2x80x94;
X is H, halo, C1-C4 alkoxy, C1-C4 alkylthio, C1-C4 alkyl, benzyloxy, hydroxy or carboxamido;
n is 1-4;
Ar is pyridinyl, pyrrolyl or a structure of Formula II: 
where R1 is H, C1-C6 alkyl, C3-C7 cycloalkyl, C3-C7 cycloalkylmethyl, benzyl, phenyl or substituted phenyl. These compounds, their synthesis, and use as serotonin 5-HT1F agonists are described in U.S. Pat. No. 5,521,196, issued May 28, 1996. This reference is hereby incorporated by reference in its entirety.
An additional class of 5-HT1F agonists are the optionally substituted 3- less than 1,2,3,6-tetrahydro- less than 1-alkylenearyl greater than -4-pyridinyl greater than -1H-indoles and 3- less than 1-alkylenearyl greater than -4-piperidinyl greater than -1H-indoles of Formula III: 
in which
Axe2x80x94B is xe2x80x94CHxe2x80x94CH2xe2x80x94 or xe2x80x94Cxe2x95x90CHxe2x80x94;
X is H, halo, C1-C4 alkoxy, C1-C4 alkylthio, C1-C4 alkyl, benzyloxy, hydroxy or carboxamido;
Y is O, S or a bond;
n is 1-4;
Ar is 1-naphthyl, 2-naphtyl, phenyl or phenyl monosubstituted with a substituent selected from the group consisting of halo, C1-C4 alkoxy, C1-C4 alkylthio, C1-C4 alkyl, benzyloxy, hydroxy or trifluoromethyl. These compounds, their synthesis, and use as serotonin 5-HT1F agonists are described in U.S. Pat. No. 5,521,197, issued May 28, 1996. This reference is hereby incorporated by reference in its entirety.
The compounds of Formulae I and III may be prepared by methods well known to the skilled artisan. Briefly, an appropriately substituted indole is reacted with an appropriate 1-substituted-4-piperidone in the presence of base to provide the corresponding 3-(1,2,3,6-tetrahydro-pyridin-4-yl)-1H-indole. These compounds may be used directly for the method of the invention or reduced to provide the corresponding 3-(piperidin-4-yl)-1H-indoles useful for the method of the invention. Compounds prepared in this matter may also serve as substrates for the preparation of other compounds useful for the method of the present invention.
A further class of compounds useful for the method of the present invention are 5-substituted-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indoles and 5-substituted-3-(piperidin-4-yl)-1H-indoles of Formula IV: 
in which
Axe2x80x94B is xe2x80x94CHxe2x80x94CH2xe2x80x94 or xe2x80x94Cxe2x95x90CHxe2x80x94;
R is H or C1-C6 alkyl;
R1 is H or C1-C4 alkyl;
X is xe2x80x94Sxe2x80x94R2, xe2x80x94C(O)R3, xe2x80x94C(O)NR4R15, xe2x80x94NR5R6, xe2x80x94R7SO2R8, xe2x80x94NHC(Q)NR10R11, xe2x80x94NHC(O)OR12 or xe2x80x94NR13C(O)R14;
xe2x80x83where
Q is O, or S;
R2 is phenyl, substituted phenyl, phenyl(C1-C4 alkylene), phenyl(C1-C4 alkylene) substituted in the phenyl ring, or pyridinyl;
R3 is C1-C6 alkyl, phenyl(C1-C4 alkylene), phenyl(C1-C4 alkylene) substituted in the phenyl ring, naphthyl, N-methyl-N-methoxyamino, heteroaryl, substituted heteroaryl, heteroaryl(C1-C4 alkyl), or substituted heteroaryl(C1-C4 alkyl);
R4 is heteroaryl, substituted heteroaryl, heteroaryl(C1-C4 alkyl), or substituted heteroaryl(C1-C4 alkyl);
R4 and R15 taken together with the nitrogen atom form a pyrrolidine, piperidine, substituted piperidine, piperazine, 4-substituted piperazine, morpholine or thiomorpholine ring;
R5 and R6 are both trifluoromethanesulfonyl;
R7 is H or C1-C4 alkyl;
R8 is C1-C4 alkyl, phenyl, substituted phenyl, or di(C1-C4 alkyl)amino;
R10 and R11 are independently selected from the group consisting of C1-C6 alkyl, C3-C6 alkenyl, C3-C8 cycloalkyl, phenyl, substituted phenyl, phenyl(C1-C4 alkylene), phenyl(C1-C4 alkylene) substituted in the phenyl ring, ((C1-C4 alkyl or C1-C4 alkoxycarbonyl substituted)C1-C4 alkyl)phenyl, C1-C4 alkyl xcex1-substituted with C1-C4 alkoxycarbonyl; or
R10 and R11 taken together with the nitrogen atom form a pyrrolidine, piperidine, piperazine, 4-substituted piperazine, morpholine or thiomorpholine ring;
R12 is C1-C6 alkyl, C3-C6 alkenyl, phenyl, substituted phenyl, C3-C8 cycloalkyl, C1-C4 alkyl xcfx89-substituted with C1-C4 alkoxy;
R13 is H or C1-C4 alkyl;
R14 is C1-C10 alkyl substituted with up to three substituents selected from the group consisting of hydroxy, C1-C4 alkoxy, halo, aryloxy, C1-C4 alkoxycarbonyl and heteroaryloxy, C2-C10 alkenyl, C2-C10 alkynyl, C3-C8 cycloalkyl, phenyl, substituted phenyl, naphthyl, phenyl(C1-C4 alkylene), phenyl(C1-C4 alkylene) substituted on the phenyl ring, 2-phenylethylen-1-yl, diphenylmethyl, benzofused C4-C8 cycloalkyl, C1-C4 alkylene xcfx89-substituted with C3-C6 cycloalkyl, or a heterocycle; and
R15 is H or C1-C6 alkyl.
The general chemical terms used in the formulae above have their usual meanings. For example, the terms xe2x80x9calkyl, alkoxy and alkylthioxe2x80x9d include such groups as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, 2-pentyl-, 3-pentyl-, neopentyl, hexyl, heptyl, octyl and the like. The term xe2x80x9calkenylxe2x80x9d includes vinyl, allyl, 1-buten-4-yl, 2-buten-4-yl, 1-penten-5-yl, 2-penten-5-yl, 3-penten-5-yl, 1-hexen-6-yl, 2-hexen-6-yl, 3-hexen-6-yl, 4-hexen-6-yl and the like. The term xe2x80x9calkynylxe2x80x9d includes acetylenyl, propynyl, 2-butyn-4-yl, 1-butyn-4-yl, 1-pentyn-5-yl, 2-pentyn-5-yl and the like. The term xe2x80x9cacylxe2x80x9d includes, for example, formyl, acetyl, propanoyl, butanoyl, and 2-methylpropanoyl. The term xe2x80x9ccycloalkylxe2x80x9d includes such groups as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl. The term xe2x80x9cphenyl(C1-C4 alkylene)xe2x80x9d includes such groups as benzyl, phenethyl, phenpropyl and phenbutyl. The term xe2x80x9c(C1-C4 alkyl)sulfonylxe2x80x9d includes methanesulfonyl, ethanesulfonyl propanesulfonyl, isopropanesulfonyl, butanesulfonyl and the like. The term xe2x80x9chaloxe2x80x9d includes fluoro, chloro, bromo and iodo.
The term xe2x80x9csubstituted phenylxe2x80x9d or xe2x80x9cphenyl(C1-C4 alkylene) substituted in the phenyl ringxe2x80x9d is taken to mean the phenyl moiety may be substituted with one substituent selected from the group consisting of halo, C1-C4 alkyl, C1-C8 alkoxy, C1-C4 alkylthio, nitro, cyano, di(C1-C4 alkyl)amino, trifluoromethyl, trifluoromethoxy, phenyl, C1-C4 acyl, benzoyl or (C1-C4 alkyl)sulfonyl, or two to three substituents independently selected from the group consisting of halo, nitro, C1-C4 alkyl, or C1-C4 alkoxy.
The term xe2x80x9cheterocyclexe2x80x9d is taken to mean stable aromatic and non-aromatic 5- and 6-membered rings containing from 1 to 3 heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur, said rings being optionally benzofused. All of these rings may be substituted with up to three substituents independently selected from the group consisting of halo, C1-C4 alkoxy, C1-C4 alkyl, cyano, nitro, hydroxy, xe2x80x94S(O)nxe2x80x94(C1-C4 alkyl) and xe2x80x94S(O)n-phenyl where n is 0, 1 or 2. Non-aromatic rings include, for example, pyrrolidinyl, piperidinyl, piperazinyl, tetrahydrofuryl, oxazolidinyl, dioxanyl, pyranyl, and the like. Benzofused non-aromatic rings include indolinyl, 1,2,3,4-tetrahydroquinolinyl, 1,2,3,4-tetrahydroisoquinolinyl and the like. Aromatic rings include furyl, thienyl, pyridinyl, pyrrolyl, N-methylpyrrolyl, oxazolyl, isoxazolyl, pyrazolyl, imidazolyl, triazolyl, oxadiazolyl, thiadiazolyl, thiazolyl, pyrimidinyl, pyrazinyl, pyridazinyl, and the like. Benzofused aromatic rings include isoquinolinyl, benzoxazolyl, benzthiazolyl, quinolinyl, benzofuranyl, thionaphthyl, indolyl and the like.
The term xe2x80x9cheteroarylxe2x80x9d is taken to mean an aromatic or benzofused aromatic heterocycle as defined in the previous paragraph. The term xe2x80x9csubstituted heteroarylxe2x80x9d is taken to mean an aromatic or benzofused aromatic heterocycle as defined in the previous paragraph substituted with up to three substituents independently selected from the group consisting of halo, C1-C4 alkoxy, C1-C4 alkyl, cyano, nitro, hydroxy, xe2x80x94S(O)nxe2x80x94(C1-C4 alkyl) and xe2x80x94S(O)n-phenyl where n is 0, 1 or 2. The term xe2x80x9cheteroaryl(C1-C4 alkyl) is taken to mean a branched or linear alkyl chain of 1 to 4 carbon atoms substituted at some point with an aromatic or benzofused aromatic heterocycle moiety. The term xe2x80x9csubstituted heteroaryl(C1-C4 alkyl)xe2x80x9d is taken to mean a branched or linear alkyl chain of 1 to 4 carbon atoms substituted at some point with an aromatic or benzofused aromatic heterocycle moiety which is substituted with up to three substituents independently selected from the group consisting of halo, C1-C4 alkoxy, C1-C4 alkyl, cyano, nitro, hydroxy, xe2x80x94S(O)nxe2x80x94(C1-C4 alkyl) and xe2x80x94S(O)n-phenyl where n is 0, 1 or 2.
The term xe2x80x9cheteroaryloxyxe2x80x9d is taken to mean a heteroaryl or substituted heteroaryl group, as defined in the previous paragraph, bonded to an oxygen atom.
The term xe2x80x9caryloxyxe2x80x9d is taken to mean a phenyl or substituted phenyl group bonded to an oxygen atom.
The term xe2x80x9c4-substituted piperazinexe2x80x9d is taken to mean a piperazine ring substituted at the 4-position with a substituent selected from the group consisting of C1-C6 alkyl, C1-C4 alkoxy substituted C1-C6 alkyl, phenyl, substituted phenyl, phenyl(C1-C4 alkylene), phenyl(C1-C4 alkylene) substituted in the phenyl ring, heteroaryl, and heteroaryl(C1-C4 alkylene).
The term xe2x80x9csubstituted piperidinexe2x80x9d is taken to mean a piperidine ring optionally substituted with a substituent selected from the group consisting of hydroxy, hydroxymethyl, and N,N-di(C1-C4 alkyl)carboxamido.
The term xe2x80x9cbenzofused C4-C8 cycloalkylxe2x80x9d is taken to mean a C4-C8 cycloalkyl group fused to a phenyl ring. Examples of these groups include benzocyclobutyl, indanyl, 1,2,3,4-tetrahydronaphthyl, and the like.
The compounds of Formula IV are prepared by methods well known to one of ordinary skill in the art, such as that generally described in U.S. Pat. No. 4,443,451, hereby incorporated by reference. While the simple indoles required for the preparation of the compounds of this invention are generally commercially available, their preparations are described in Robinson, The Fischer Indole Synthesis, Wiley, New York (1983); Hamel, et al., Journal of Organic Chemistry, 59, 6372 (1994); and Russell, et al., Organic Preparations and Procedures International, 17, 391 (1985).
The compounds of the invention where X is xe2x80x94NR7SO2R8 may be prepared by first modifying an appropriate 5-aminoindole. When R7 is hydrogen, the 5-aminoindole is reacted with an appropriate sulfonyl halide or anhydride to give the corresponding sulfonamide. When R7 is lower alkyl, however, the 5-aminoindole is first acylated, and then reduced with an appropriate hydride reducing agent. Alternatively, the 5-aminoindole may be reductively alkylated with an appropriate aldehyde or ketone in the presence of a suitable hydride reducing agent to give the appropriately substituted indole. These substituted indoles are then reacted with a sulfonyl halide or anhydride to give the corresponding sulfonamide. This chemistry is illustrated in Synthetic Scheme I, where M is methoxy, ethoxy, methyl, ethyl, propyl, or isopropyl, LG is chloro or bromo, and R1, R7, and R8 are as defined supra. 
When R7 is to be hydrogen, a solution of 5-aminoindole in a suitable solvent, such as tetrahydrofuran, dioxane, diethyl ether or dimethylformamide, at a temperature from about ambient to about 0xc2x0 C., is reacted with a commercially available R8-sulfonyl halide or R8-sulfonic anhydride in the presence of a suitable base such as pyridine or triethylamine. The resultant sulfonamide may be isolated by dilution of the reaction mixture with water, adjustment of pH, and extraction with a water immiscible solvent such as dichloromethane. The product may be used for further reaction as recovered, or may be purified by chromatography, or by recrystallization from a suitable solvent.
When R7 is to be lower alkyl, a solution of 5-aminoindole in a suitable solvent, such as tetrahydrofuran, dioxane, or diethyl ether, at a temperature from about ambient to about 0xc2x0 C., is reacted with a compound of structure Mxe2x80x94C(O)-halo in the presence of a suitable base such as pyridine or triethylamine. The resultant compound is isolated by dilution of the reaction mixture with water and extraction with a water immiscible solvent such as dichloromethane. This acylated product may either be purified chromatographically or used directly in the subsequent step. The acylated product is then dissolved in a suitable solvent, such as tetrahydrofuran or diethyl ether, at a temperature from about ambient to about 0xc2x0 C., and is treated with a suitable hydride reducing agent such as diborane or lithium aluminum hydride. The reaction is stirred from 1 to 24 hours and is then treated with aqueous solution of sodium sulfate. The resultant suspension is filtered, and the filtrate concentrated under reduced pressure. The product may be used for further reaction as is, purified by chromatography, or recrystallized from a suitable solvent.
Alternatively, a solution of a 5-aminoindole in a solvent suitable for the azeotropic removal of water, such as toluene, benzene or cyclohexane, is reacted at reflux with an appropriate aldehyde or ketone, such as formaldehyde, acetaldehyde, propanal, butanal or acetone, in the presence of 0.1-10% of a proton source such as p-toluenesulfonic acid. When the reaction is complete the volatiles are removed under reduced pressure and the residue redissolved in an alkanol such as methanol or ethanol. This solution is then subjected to hydrogenation conditions, or is treated with an appropriate hydride reducing agent, such as sodium borohydride or, preferably, sodium cyanoborohydride in the presence of an anhydrous acid such as hydrogen chloride. The reaction is then diluted with water, treated with base and extracted into a water immiscible solvent such as dichloromethane. The product may be used as is for further reaction, purified by chromatography or crystallized from a suitable solvent. This product is now treated with a commercially available R8-sulfonyl halide or R8-sulfonic anhydride as described supra to give the required sulfonamides.
Compounds of the invention where X is xe2x80x94Sxe2x80x94R2, xe2x80x94C(O)R3 or xe2x80x94C(O)NR4R15 are prepared by first converting a 5-bromoindole into a 5-bromo-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or 5-bromo-3-(1-piperidin-4-yl)-1H-indole. Compounds of the invention where X is xe2x80x94NR5R6, xe2x80x94NHC(Q)NR10R11, xe2x80x94NHC(O)OR12 or xe2x80x94NR13C(O)R14 are prepared by first converting a 5-nitro- or 5-aminoindole into a 5-nitro- or 5-amino-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or into the corresponding 5-nitro- or 5-amino-(1-piperidin-4-yl)-1H-indole. Compounds of the invention where X is xe2x80x94NR7SO2R8 or xe2x80x94NR13C(O)R14 may be prepared by converting the appropriately substituted indole into the corresponding 3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or 3-(1-piperidin-4-yl)-1H-indole. This chemistry is illustrated in Synthetic Scheme II, where Y is nitro, amino, bromo, xe2x80x94NR13C(O)R14, or xe2x80x94NR7SO2R8, and R, R1, R7, R8, R13 and R14 are as defined supra. 
The 5-substituted indole is condensed with a 4-piperidone in the presence of a suitable base to give the corresponding 5-substituted-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole. The reaction is performed by first dissolving an excess of the base, typically sodium or potassium hydroxide, in a lower alkanol, typically methanol or ethanol. The indole and two equivalents of the 4-piperidone are then added and the reaction refluxed for 8-72 hours. The resulting 5-substituted-3-(1,2,3,6-tetrahydro-pyridin-4-yl)-1H-indoles may be isolated from the reaction mixture by the addition of water. Compounds which precipitate may be isolated directly by filtration while others may be extracted by adjusting the pH of the solution and extracting with a water immiscible solvent such as ethyl acetate or dichloromethane. The compounds recovered may be used directly in subsequent steps or first purified by silica gel chromatography or recrystallization from a suitable solvent.
The 5-substituted-3-(1-substituted-1,2,3,6-tetrahydro-pyridin-4-yl)-1H-indoles may be used to prepare other compounds of the invention or, if desired, may be hydrogenated over a precious metal catalyst, such as palladium on carbon, to give the corresponding 5-substituted-3-(piperidin-4-yl)-1H-indoles. When Y is bromo, a hydrogenation catalyst such as sulfided platinum on carbon, platinum oxide, or a mixed catalyst system of sulfided platinum on carbon with platinum oxide is used to prevent hydrogenolysis of the 5-bromo substituent during reduction of the tetrahydro-pyridinyl double bond. The hydrogenation solvent may consist of a lower alkanol, such as methanol or ethanol, tetrahydrofuran, or a mixed solvent system of tetrahydrofuran and ethyl acetate. The hydrogenation may be performed at an initial hydrogen pressure of 20-80 p.s.i., preferably from 50-60 p.s.i., at 0-60xc2x0 C., preferably at ambient temperature to 40xc2x0 C., for 1 hour to 3 days. Additional charges of hydrogen may be required to drive the reaction to completion depending on the specific substrate. The 5-substituted-3-(piperidin-4-yl)-1H-indoles prepared in this manner are isolated by removal of the catalyst by filtration followed by concentration of the reaction solvent under reduced pressure. The product recovered may be used directly in a subsequent step or further purified by chromatography, or by recrystallization from a suitable solvent.
As an alternative to hydrogenation, the 5-substituted-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indoles may be converted to the corresponding 5-substituted-3-(piperidin-4-yl)-1H-indoles by treatment with trifluoroacetic acid/triethylsilane if desired. The 5-substituted-3-(1-substituted-1,2,5,6-tetrahydro-4-pyridinyl)-1H-indole is dissolved in trifluoroacetic acid to which is added an excess, 1.1-10.0 equivalents, of triethylsilane. The reaction mixture is stirred at about ambient temperature for from about 1 to about 48 hours at which time the reaction mixture is concentrated under reduced pressure. The residue is then treated with 2N sodium or potassium hydroxide and the mixture extracted with a water immiscible solvent such as dichloromethane or diethyl ether. The resultant 5-substituted-3-(piperidin-4-yl)-1H-indole is purified by column chromatography if desired.
The skilled artisan will appreciate that the 5-nitro substituent may be reduced before or after condensation with an appropriate 4-piperidone. Additionally, the nitro group and the 1,2,3,6-tetrahydropyridinyl double bond may be hydrogenated simultaneously if desired.
Compounds where X is xe2x80x94Sxe2x80x94R2 are prepared from the corresponding 5-bromo-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indoles or 5-bromo-3-(piperidin-4-yl)-1H-indoles as illustrated in Synthetic Scheme III, where A, B, R1 and R2 are as defined supra and R=C1-C4 alkyl. 
The 5-bromo-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indoles or 5-bromo-3-(piperidin-4-yl)-1H-indoles in a suitable aprotic solvent, such as diethyl ether or tetrahydrofuran, are cooled to about 0xc2x0 C. and treated with potassium hydride to deprotonate the indole nucleus at the 1-position. While other hydrides are useful for this deprotonation, the resultant potassium salt is more soluble in typical reaction solvents. The reaction mixture is then cooled to about xe2x88x9278xc2x0 C. and halogen-metal exchange effected by the addition of two equivalents of t-butyllithium. To this dianion solution are then added an appropriate disulfide and the reaction mixture allowed to warm to ambient temperature. The compound of the invention is isolated by treating the reaction mixture with aqueous base, such as sodium or potassium hydroxide, and then extracting with a water immisible solvent such as diethyl ether or dichloromethane. The reaction product may then be purified by column chromatography.
Compounds where X is xe2x80x94C(O)R3 or xe2x80x94C(O)NR4R15 are prepared from the corresponding 5-bromo-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indoles or 5-bromo-3-(piperidin-4-yl)-1H-indoles as illustrated in Synthetic Scheme IV, where A, B, R1, R3, R4 and R15 are as defined supra and R=C1-C4 alkyl. 
The dianion of the 5-bromo-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indoles or 5-bromo-3-(1-substituted-piperidin-4-yl)-1H-indole, prepared as described supra, is then treated with N,Nxe2x80x2-dimethyl-N,Nxe2x80x2-dimethoxyurea. The resulting N-methyl-N-methoxy-5-carboxamido-1H-indole is isolated by treating the reaction mixture with aqueous base, such as sodium or potassium hydroxide, and then extracting with a water immisible solvent such as diethyl ether or dichloromethane. The reaction product may then be purified by column chromatography.
Compounds where X is xe2x80x94C(O)R3 are prepared by reacting a solution of the N-methyl-N-methoxy-5-carboxamido-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or N-methyl-N-methoxy-5-carboxamido-3-(piperidin-4-yl)-1H-indole in a suitable solvent, such as diethyl ether or tetrahydrofuran, at about 0xc2x0 C., with an appropriate reagent such as an aryl- or alkyllithium or an alkyl or aryl Grignard reagent. These reagents are either commercially available or may be prepared by methods well known to one of ordinary skill in the art. The aryl- or alkyllithium reagents are conveniently prepared by treating an appropriate aryl or alkyl halide with n-butyllithium. The aryl or alkyl Grignard reagents may be prepared by treating an appropriate aryl or alkyl halide with magnesium. The compounds of interest may be isolated by aqueous work-up followed by extraction into a water immiscible solvent such as diethyl ether or dichloromethane, and then purified by chromatography, or by recrystallization from a suitable solvent.
The skilled artisan will also appreciate that the compounds where X is xe2x80x94C(O)R3 are also available by the reaction of the dianion of either a 5-bromo-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or a 5-bromo-3-(piperidin-4-yl)-1H-indole with an appropriate aryl or alkyl N-methyl-N-methoxycarboxamide. These carboxamides are prepared from the corresponding carboxylic acids and N-methyl-N-methoxyamine under standard peptide coupling conditions using N,Nxe2x80x2-dicyclohexylcarbodiimide.
Compounds where X is xe2x80x94C(O)NR4R15 are prepared by reacting a solution of the N-methyl-N-methoxy-5-carboxamido-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or N-methyl-N-methoxy-5-carboxamido-3-(piperidin-4-yl)-1H-indole in a suitable solvent, such as diethyl ether or tetrahydrofuran, at about 0xc2x0 C., with the anion of an appropriate amine. These anions are prepared by treating the appropriate amine with n-butyllithium. The compounds of interest may be isolated by aqueous work-up followed by extraction into a water immiscible solvent such as diethyl ether or dichloromethane, and then purified by chromatography, or by recrystallization from a suitable solvent.
Alternatively, compounds where X is xe2x80x94C(O)NR4R15 are prepared by subjecting an appropriate indole 5-carboxylic acid and an appropriate amine to standard peptide coupling conditions. The indole 5-carboxylic acid in an appropriate solvent may be treated with oxalyl chloride, thionyl chloride or phosphorous tribromide in an appropriate solvent, for example toluene, to prepare the corresponding acid halide. The acid halide in a suitable solvent, for example tetrahydrofuran or dimethylformamide, may be treated with an amine of formula HNR4R14 in the presence of a suitable base such as triethylamine, pyridine or dimethylaminopyridine to provide the desired compound. The product may be isolated by aqueous work-up followed by extraction into a water immiscible solvent such as diethyl ether, ethyl acetate or dichloromethane, and then purified by chromatography, or by recrystallization from a suitable solvent.
Preferably, compounds where X is xe2x80x94C(O)NR4R15 are prepared by reacting the appropriate indole 5-carboxylic acid with an appropriate amine in the presence of typical peptide coupling reagents such as N,Nxe2x80x2-carbonyldiimidazole (CDI), N,Nxe2x80x2-dicyclohexylcarbodiimide (DCC) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC).
Compounds where X is xe2x80x94NR5R6, xe2x80x94NHC(Q)NR10R11, xe2x80x94NHC(O)OR12 or xe2x80x94NR13C(O)R14 are prepared by reacting the appropriate 5-amino-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or 5-amino-3-(piperidin-4-yl)-1H-indole with a suitable electrophile. These reactions are illustrated in Synthetic Scheme V, where A, B, R1, R5, R6, R10, R11, R12, R13 and R14 are as described supra and R=C1-C4 alkyl. 
Compounds where X is xe2x80x94NR5R6 are prepared by treating a solution of the 5-amino-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or 5-amino-3-(piperidin-4-yl)-1H-indole in a suitable solvent, such as dichloromethane, tetrahydrofuran, acetonitrile or dimethylformamide, with a suitable electrophile, such as trifluoromethanesulfonic anhydride or N-carbethoxyphthalimide, in the presence of a suitable base such as pyridine or triethylamine. The reaction product is isolated by evaporation of the reaction solvent under reduced pressure. The product may be purified by chromatography, or by crystallization from an appropriate solvent.
Compounds where X is xe2x80x94NHC(Q)NR10R11 are prepared by treating a solution of the 5-amino-3-(1,2,3,6-tetrahydro-pyridin-4-yl)-1H-indole or 5-amino-3-(piperidin-4-yl)-1H-indole in a suitable solvent, such as chloroform or dichloromethane, with an appropriate isocyanate, isothiocyanate, carbamoyl chloride or carbamoyl bromide. Appropriate carbamoyl chlorides are available by treating an amine of formula HNR10R11 with phosgene. When a carbamoyl chloride or carbamoyl bromide is used, the reactions are performed in the presence of a suitable base. Suitable bases include amines typically used as acid scavengers, such as pyridine or triethylamine, or commercially available polymer bound bases such as polyvinylpyridine. If necessary, an excess of the isocyanate, isothiocyanate, carbamoyl chloride or carbamoyl bromide is employed to ensure complete reaction of the starting amine. The reactions are performed at about ambient to about 80xc2x0 C., for from about three hours to about three days. Typically, the product may be isolated by washing the reaction mixture with water and concentrating the remaining organics under reduced pressure. When an excess of isocyanate, isothiocyanate, carbamoyl chloride or carbamoyl bromide has been used, however, a polymer bound primary or secondary amine, such as an aminomethylated polystyrene, may be conveniently added to react with the excess reagent. Isolation of products from reactions where a polymer bound reagent has been used is greatly simplified, requiring only filtration of the reaction mixture and then concentration of the filtrate under reduced pressure. The product from these reactions may be purified chromatographically or recrystallized from a suitable solvent if desired. The skilled artisan will appreciate that compounds which are ureas may be converted into the corresponding thiourea by treatment with [2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide] (Lawesson""s Reagent) or phosphorus pentasulfide.
Compounds where X is xe2x80x94NHC(O)OR12 are prepared by reacting the 5-amino-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or 5-amino-3-(piperidin-4-yl)-1H-indole with an appropriately substituted chloroformate in the presence of a suitable amine under the conditions described in the previous paragraph. Likewise, compounds where X is xe2x80x94NR13C(O)R14 are prepared by reacting the 5-amino-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or 5-amino-3-(piperidin-4-yl)-1H-indole with an appropriate carboxylic acid chloride, bromide or anhydride, optionally in the presence of an acylation catalyst such as dimethylaminopyridine, in the presence of a suitable base, such as those described supra.
Alternatively, compounds where X is xe2x80x94NR13C(O)R14 are prepared by reacting the 5-amino-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole or 5-amino-3-(piperidin-4-yl)-1H-indole with an appropriate carboxylic acid halide, carboxylic acid anhydride, or a carboxylic acid in the presence of typical peptide coupling reagents such as N,Nxe2x80x2-carbonyldiimidazole (CDI), N,Nxe2x80x2-dicyclohexylcarbodiimide (DCC) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC). A polymer supported form of EDC has been described (Tetrahedron Letters, 34(48), 7685 (1993)) and is very useful for the preparation of the compounds of the present invention. The product from these reactions is isolated and purified as described above.
The skilled artisan will appreciate that the order in which the steps are performed to prepare these compounds is not important in many cases. For example, compounds where X is xe2x80x94NR7SO2R8 are accessible by subjecting the 5-amino-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indoles or 5-amino-3-(piperidin-4-yl)-1H-indoles to the conditions illustrated in Synthetic Scheme I. Likewise, 5-aminoindole may be subjected to the reaction sequences illustrated in Synthetic Scheme V prior to reaction with a 4-piperidone as illustrated in Synthetic Scheme II. The skilled artisan will also appreciate that compounds where R is H may be prepared by condensing 4-piperidone with a suitably substituted indole to give the corresponding 3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indoles which may then be hydrogenated if desired. Alternatively, 1-benzyl-4-piperidone may be substituted at any point in the synthesis for a suitably substituted 4-piperidone. The benzyl group may then be removed by standard hydrogenation conditions after reactions for which the secondary amine would be incompatible are complete. The 3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indoles may also be reduced to the corresponding 3-(piperidin-4-yl)-1H-indoles at any convenient point in the synthetic sequence. These variations are made apparent in the following Preparations and Examples.
To a solution of 56.11 gm (306 mMol) potassium hydroxide in 300 mL methanol were added 38 mL (306 mMol) 1-methyl-4-piperidone followed by 30.0 gm (153 mMol) 5-bromo-1H-indole. The reaction mixture was stirred at reflux for 18 hours. The reaction mixture was then cooled to ambient and diluted with 1.5 L water. The resultant white solid was filtered, washed sequentially with water and diethyl ether, and then dried under vacuum to give 44.6 gm (100%) 5-bromo-3-(1-methyl-1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole.
Catalytic Hydrogenation
To a solution of 44.6 gm (153 mMol) 5-bromo-3-(1-methyl-1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole in 1.95 L tetrahydrofuran were added 9.0 gm platinum oxide. The reaction mixture was hydrogenated with an initial hydrogen pressure of 60 p.s.i. at ambient temperature for 24 hours. The reaction mixture was filtered and the filtrate concentrated under reduced pressure. The residue was recrystallized from acetonitrile to give 32.6 gm (73.7%) of the title compound as a white solid.
MS(m/e): 293(M+).
Calculated for C14H17N2Br: Theory: C, 57.32; H, 5.96; N, 9.69. Found: C, 57.35; H, 5.84; N, 9.55.
To a suspension of 0.72 gm (3.58 mMol) potassium hydride in 16.0 mL tetrahydrofuran at 0xc2x0 C. was added a solution of 1.0 gm (3.41 mMol) 5-bromo-3-(1-methylpiperidin-4-yl)-1H-indole in 16.0 mL tetrahydrofuran and the solution stirred for about 30 minutes. The resulting mixture was cooled to about xe2x88x9278xc2x0 C. and to it were added 4.4 mL (7.5 mMol) t-butyl lithium, which had been precooled to xe2x88x9278xc2x0 C., via cannula. After about 15 minutes 0.66 gm (3.41 mMol) N,Nxe2x80x2-dimethyl-N,Nxe2x80x2-dimethoxyurea were added and the reaction mixture was allowed to warm gradually to ambient. The reaction mixture was then treated with 5N sodium hydroxide and extracted with diethyl ether. The ether extracts were combined, washed with saturated aqueous sodium chloride, dried over sodium sulfate and concentrated under reduced pressure. Purification by flash chromatography, eluting with 4.5:0.5:0.2 ethyl acetate:methanol:toluene, gave 0.61 gm (60%) of the title compound.
MS(m/e): 301(M+)
IR: 1632 cmxe2x88x921 
Calculated for C17H23N3O2.0.25 H2O: Theory: C, 66.75; H, 7.74; N, 13.73. Found: C, 66.47; H, 7.72; N, 13.69.
To a solution of 2.0 gm (11.4 mMol) 2-methyl-5-nitro-1H-indole in 100 mL 1:1 ethanol:tetrahydrofuran were added 0.25 gm 5% palladium on carbon. The suspension was hydrogenated at ambient temperature at an initial hydrogen pressure of 60 p.s.i. After 5 hours the reaction mixture was filtered and the filtrate concentrated under reduced pressure to give 1.5 gm of a dark brown solid. The solid was purified by flash chromatography, eluting with a gradient of dichloromethane containing 0-3% methanol, to give 1.19 gm (71.7%) of the title compound as light brown plates.
m.p.=154-156xc2x0 C.
MS(m/e): 147(M+1)
Calculated for C9H10N2: Theory: C, 73.94; H, 6.89; N, 19.16. Found: C, 74.15; H, 6.93; N, 19.27.
Many of the 5-(C1-C4 alkyl)amino-1H-indoles required for the preparation of compounds of the invention are available through the procedure described in Preparation IV.
To a solution of 4.27 gm (32.3 mMol) 5-amino-1H-indole in 50 mL tetrahydrofuran were added 5.4 mL (38.8 mMol) triethylamine and the reaction mixture was then cooled to 0xc2x0 C. To this solution were then added dropwise 3.4 mL (35.5 mMol) ethyl chloroformate. After 4 hours the reaction mixture was diluted with 1N HCl and was then extracted with ethyl acetate. The organic phase was washed sequentially with 1N HCl, water and saturated aqueous sodium chloride. The remaining organics were dried over sodium sulfate and concentrated under reduced pressure to give 7.4 gm of a dark oil. This oil was purified by flash chromatography, eluting with a gradient of dichloromethane containing 0-2.5% methanol, to give 4.95 gm (75%) of the title compound as a tan solid.
m.p.=113-114xc2x0 C.
MS(m/e): 204(M+)
Calculated for C11H12N2O2: Theory: C, 64.69; H, 5.92; N, 13.72. Found: C, 64.76; H, 5.92; N, 13.76.
To a suspension of 6.3 gm (164.5 mMol) lithium aluminum hydride in 50 mL tetrahydrofuran was added dropwise a solution of 4.8 gm (23.5 mMol) N-ethoxycarbonyl-5-amino-1H-indole in 40 mL tetrahydrofuran. The reaction mixture was heated to reflux until the starting material was consumed as measured by thin-layer chromatography. The reaction mixture was then cooled to ambient and treated with saturated aqueous sodium sulfate to destroy excess lithium aluminum hydride. The resulting suspension was filtered and the filtrate concentrated under reduced pressure to give 3.6 gm of a dark solid. The solid was subjected to flash chromatography, eluting with a gradient of dichloromethane containing 0-2% methanol, to give 3.3 gm (97.1%) of the title compound as a tan solid.
MS(m/e): 146(M+)
Calculated for C9H10N2: Theory: C, 73,94; H, 6.90; N, 19.16. Found: C, 73.78; H, 6.94; N, 19.04.
All of the 5-sulfonamido-1H-indoles required for the preparation of compounds of the invention are available by treating 5-amino-1H-indole with an appropriate sulfonyl chloride as described in Preparation V.
To a solution of 2.0 gm (15.1 mMol) 5-amino-1H-indole in 25 mL tetrahydrofuran were added 2.4 mL (17.2 mMol) triethylamine. The reaction mixture was cooled in an ice bath as 1.23 mL (15.9 mMol) methanesulfonyl chloride were added dropwise. After 3.5 hours the reaction mixture was partitioned between 1N sodium hydroxide and ethyl acetate. The organic phase was extracted twice with 1N sodium hydroxide. All sodium hydroxide phases were combined, adjusted to pH=5 with acid and extracted well with ethyl acetate. These organic phases were combined, washed sequentially with water and saturated aqueous sodium chloride, dried over sodium sulfate and concentrated under reduced pressure to give 3.0 gm of a purple solid. This solid was crystallized from cyclohexane/ethyl acetate to give 2.5 gm (78.6%) of the title compound as light purple crystals.
m.p.=133-135xc2x0 C.
MS(m/e): 210(M+)
Calculated for C9H13N2O2S: Theory: C, 51.41; H, 4.79; N, 13.32. Found: C, 51.16; H, 4.93; N, 13.27.
To a solution of 10.38 gm (185 mMol) potassium hydroxide in 200 mL methanol were added 10.0 gm (61.7 mMol) 5-nitro-1H-indole followed by 13.96 gm (123 mMol) 1-methyl-4-piperidone. The mixture was heated to reflux for 4 days under a nitrogen atmosphere. The reaction mixture was then allowed to cool to ambient and the solid which formed filtered and washed with methanol. This solid was dried under vacuum at 50xc2x0 C. The combined filtrates were then concentrated under reduced pressure and the residue subjected to flash chromatography, eluting with 92.5:7.5 dichloromethane:methanol. Fractions shown to contain product were combined and concentrated under reduced pressure. This solid was combined with that isolated directly from the reaction mixture to give 13.79 gm (87%) 5-nitro-3-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)-1H-indole.
To a solution of 38.2 gm (145 mMol) 5-nitro-3-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)-1H-indole in 1.9 L ethanol and 30 mL 5N HCl were added 10.0 gm 5% palladium on carbon. The reaction mixture was hydrogenated at ambient for 18 hours with an initial hydrogen pressure of 60 p.s.i. The reaction mixture was filtered and then concentrated under reduced pressure. The residue was dissolved in methanol and the solution filtered. This filtrate was concentrated under reduced pressure and the residue redissolved in ethanol. The solution was concentrated to about 500 mL and product allowed to crystallize. The crystals were filtered to give 48.9 gm (95%) of the title compound as its dihydrochloride salt, ethanol solvate.
m.p.=310-320xc2x0 C. (dec.)
MS(m/e): 229(M+)
Calculated for C14H19N3.2HCl.C2H6O: Theory: C, 55.17; H, 7.81; N, 12.06. Found: C, 55.23; H, 7.61; N, 12.30.
To a solution of 1.29 gm (20 mMol) potassium hydroxide in 10 mL methanol were added 1.32 gm (10 mMol) 5-amino-1H-indole followed by 2.46 mL (20 mMol) 1-methyl-4-piperidone. The reaction mixture was then heated to reflux for 18 hours. The reaction mixture was cooled to ambient, diluted with 20 ml water and the precipitate collected by filtration. The solid was recrystallized from ethyl acetate:methanol to give 1.11 gm (48.9%) 5-amino-3-(1-methyl-1,2,3,6-tetrahydropyr-idin-4-yl)-1H-indole as a tan solid (m.p.=200-203xc2x0 C.). The tan solid was subjected to flash chromatography, eluting with 100:20:0.5 dichloromethane:methanol:ammonium hydroxide, to give 0.99 gm 5-amino-3-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)-1H-indole as a cream colored solid (m.p.=212-215xc2x0 C. (ethyl acetate:methanol)).
MS(m/e): 227(M+)
Calculated for C14H17N3: Theory: C, 73.98; H, 7.54; N, 18.49. Found: C, 73.76; H, 7.48; N, 18.22.
To a solution of 11.3 gm (50 mMol) 5-amino-3-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)-1H-indole in 250 mL methanol were added 3.0 gm 5% palladium on carbon. The mixture was hydrogenated at room temperature under an initial hydrogen pressure of 60 p.s.i. for 18 hours. The reaction mixture was filtered and the filtrate concentrated under reduced pressure to give a dark gum which was slurried in hexane to give the title compound as a brown solid.
MS(m/e): 229(M+)
To a solution of 11.38 gm (116.7 mMol) N-methoxy-N-methyl amine hydrochloride in 700 mL 1N sodium hydroxide was added a solution of 18.56 gm (106.04 mMol) 4-chlorobenzoyl chloride in 200 mL dichloromethane and the mixture was stirred at ambient. After 18 hours the phases were separated and the remaining aqueous was extracted well with dichloromethane. All organic phases were combined, dried over sodium sulfate and concentrated under reduced pressure to give 27.9 gm (95%) of the title compound as a clear oil.
MS(m/e): 165(M+)
IR: 3011, 2974, 2938, 1634 cmxe2x88x921 
To a solution of 5.8 gm (90 mMol) potassium hydroxide in 50 mL methanol were added 4.83 gm (30 mMol) indole 5-carboxylic acid followed by 7.4 mL (60 mMol) 1-methyl-4-piperidone and the resulting solution was heated at reflux for 18 hours. The reaction mixture was then concentrated under reduced pressure and the resulting oil dissolved in 200 mL water. The solution was gradually neutralized by addition of 18 mL 5 N hydrochloric acid. The precipitate which formed was isolated by filtration and washed with water to provide 6.09 gm after drying. This solid was dissolved in 100 mL 0.5 N sodium hydroxide, filtered and the filtrate treated with 50 mL 1N hydrochloric acid. The solid which formed was filtered and dried under reduced pressure to provide 5.46 gm (71%) of the title compound.
m.p.=249xc2x0 C.
MS(m/e): 256(M+)
Calculated for C15H16N2O2: Theory: C, 70.29; H, 6.29; N, 10.93. Found: C, 70.02; H, 6.39; N, 11.02.
A solution of 0.513 gm (2 mMol) 5-carboxy-3-(1-methyl-1,2,5,6-tetrahydropyridin-4-yl)-1H-indole in 5.1 mL ethanol was cooled in an ice bath while 0.51 mL sulfuric acid was added dropwise. The resulting mixture was heated at reflux for 5 hours. The now homogeneous solution was poured into 50 mL cold water and was then made basic with saturated ammonium hydroxide. The light yellow precipitate was collected by filtration and then recrystallized from ethanol to provide 0.24 gm (42%) of the desired compound as light yellow crystals.
m.p.=249xc2x0 C.
MS(m/e): 284(M+)
Calculated for C17H20N2O2: Theory: C, 71.81; H, 7.09; N, 9.85. Found: C, 71.97; H, 7.25; N, 9.71.
To a solution of 3.24 gm (11.3 mMol) 5-ethoxycarbonyl-3-(1-methyl-1,2,5,6-tetrahydropyridin-4-yl)-1H-indole in 100 mL ethanol was added 0.8 gm 5% palladium an carbon and the reaction mixture hydrogenated at room temperature for 18 hours at an initial hydrogen pressure of 60 p.s.i. The reaction mixture was filtered and the filtrate concentrated under reduced pressure. The residual oil, which crystallized on standing at room temperature, was recrystallized from 30 mL acetonitrile to provide 1.79 gm (55%) of the desired compound as colorless crystals.
m.p.=155-157xc2x0 C.
MS(m/e): 286(M+)
Calculated for C17H22N2O2: Theory: C, 71.30; H, 7.74; N, 9.78. Found: C, 71.07; H, 7.88; N, 9.73.
Saponification/protonation
A mixture of 0.859 gm (3 mMol) 5-ethoxycarbonyl-3-(1-methylpiperidin-4-yl)-1H-indole, 6.0 mL ethanol and 6 mL 2N sodium hydroxide were heated at reflux for 2 hours. Ethanol was distilled from the resulting solution and the remaining aqueous solution was neutralized with 2.4 mL 5N hydrochloric acid. The resulting oil suspended in water is treated with a small amount of dichloromethane and cooled. The resulting solid is filtered, washed with water and acetone, and then recrystallized from 15 mL water to provide 0.308 gm (40%) of the title compound as colorless crystals.
m.p. greater than 280xc2x0 C.
MS(m/e): 258(M+)
Calculated for C15H18N2O2: Theory: C, 69.74; H, 7.02; N, 10.84. Found: C, 69.66; H, 7.03; N, 10.92.
To a stirred suspension of 50 gm (61 mMol) aminomethylated polystyrene resin (1.22 mMol/gm) in 800 mL toluene was added 193 mL (366 mMol) 1.9 M phosgene in toluene. After stirring the reaction mixture for 10 minutes, 67 mL (482 mMol) triethylamine was added and the reaction mixture was stirred for 18 hours at room temperature. The mixture was filtered and the recovered solid washed with 10 times with dichloromethane. A light pink resin mixed with a white solid was obtained. This solid mixture was resuspended in 700 mL dichloromethane, stirred for 10 minutes and then filtered and washed well with dichloromethane. The resulting solid was again suspended, stirred and washed with dichloromethane to provide the desired resin.
IR(KBr): 2252 cmxe2x88x921 (characteristic peak for xe2x80x94Nxe2x95x90Cxe2x95x90O)